更改UITextView中一个链接的属性 [英] Change attributes of one link in UITextView

问题描述

我有一个UITextView，其中有多个URL，可以通过将dataDetectorTypes属性设置为UIDataDetectorTypeLink来激活.然后，我使用linkTextAttributes属性设置链接的颜色.现在，当用户点击一个链接(使用UITapGestureRecognizer)时，我只想更改该链接的颜色.如果我更改linkTextAttributes，则所有链接都会更改颜色.

I have a UITextView with multiple URLs that I activate by setting the dataDetectorTypes property to UIDataDetectorTypeLink. I then use the linkTextAttributes property to set the color of the links. Now when the user taps on one of the links (using a UITapGestureRecognizer), I'd like to change the color of that link only. If I change linkTextAttributes, all the links will change color.

如何仅更改被点击链接的颜色?

How can I change just the color of the link that was tapped on?

推荐答案

我想我通过使用UITextView的具有rangeOfLink属性的子类解决了这个问题.

I think I solved it, using a subclass of UITextView called which has a rangeOfLink property.

首先，在我的UIViewController viewDidLoad:中，添加

First, in my UIViewController viewDidLoad:, I add

self.textView.dataDetectorTypes = UIDataDetectorTypeLink; // change for other link types
self.textView.selectable = YES;
self.textView.userInteractionEnabled = YES;

UITapGestureRecognizer *tapGesture = [[UITapGestureRecognizer alloc] initWithTarget: self action: @selector(handleTap:)];
tapGesture.cancelsTouchesInView = YES;

[self.textView addGestureRecognizer: tapGesture];
[self.textView setNeedsDisplay]; // force a redraw so that drawRect is called

然后在handleTap中，我这样做:

MyTextViewWithLink *aTextView = (IDTextViewWithLink *) recognizer.view;

if (aTextView != self.textView)
    return;

if (recognizer.state == UIGestureRecognizerStateEnded)
{
    CGPoint location = [recognizer locationInView: aTextView];

 // this returns an NSTextCheckingResult if location is inside a link
    NSTextCheckingResult *result = [self textCheckingResultAtPoint: location inTextView: aTextView]; 

    if (result)
    {
        aTextView.rangeOfLink = result.range;
        [aTextView setNeedsDisplay]; // this will force the color change

        // open url
    }
}

最后，我在UITextView子类中覆盖了drawRect:

Finally I override drawRect in my UITextView subclass:

self.linkTextAttributes = [NSDictionary dictionary];

NSError *error = nil;
NSDataDetector *dataDetector = [NSDataDetector dataDetectorWithTypes: NSTextCheckingTypeLink error: &error];  // change for other link types

if (!error && dataDetector)
{
    NSArray* resultString = [dataDetector matchesInString: self.text
                                              options: NSMatchingReportProgress
                                                range: NSMakeRange(0, [self.text length])];
    if (resultString.count > 0)
    {
        NSMutableAttributedString *mas = [self.attributedText mutableCopy];

        for (NSTextCheckingResult* result in resultString)
        {
            if (result.resultType == NSTextCheckingTypeLink)
            {
                NSRange intersection = NSIntersectionRange(result.range, self.rangeOfLink);

                if (intersection.length <= 0) // no match
                    [mas addAttribute: NSForegroundColorAttributeName
                                value: [UIColor blueColor]
                                range: self.rangeOfLink];
                else
                    [mas addAttribute: NSForegroundColorAttributeName
                                value: [UIColor redColor]
                                range: self.rangeOfLink];
            }
        }

        self.attributedText = mas;
    }
}

[super drawRect: rect];

现在，如果textView具有多个链接，则只有选定的链接会更改颜色.

Now if the textView has more than one link, only the selected one will change color.

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